upgrade docker base images

Dockerfile

@@ -1,19 +1,19 @@
-FROM ubuntu:18.04 as builder
+FROM ubuntu:20.04 as builder
 LABEL maintainer michel.promonet@free.fr
 WORKDIR /v4l2rtspserver
 COPY . /v4l2rtspserver
 
 RUN apt-get update \
-    && apt-get install -y --no-install-recommends ca-certificates g++ autoconf automake libtool xz-utils cmake make pkg-config git wget libasound2-dev \
+    && DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends ca-certificates g++ autoconf automake libtool xz-utils cmake make pkg-config git wget libasound2-dev \
     && cmake . && make install && apt-get clean && rm -rf /var/lib/apt/lists/
 
-FROM ubuntu:18.04
+FROM ubuntu:20.04
 WORKDIR /usr/local/share/v4l2rtspserver
 COPY --from=builder /usr/local/bin/ /usr/local/bin/
 COPY --from=builder /usr/local/share/v4l2rtspserver/ /usr/local/share/v4l2rtspserver/
 
 RUN apt-get update \
-    && apt-get install -y --no-install-recommends ca-certificates libasound2 && apt-get clean && rm -rf /var/lib/apt/lists/
+    && DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends ca-certificates libasound2 && apt-get clean && rm -rf /var/lib/apt/lists/
 
 ENTRYPOINT [ "/usr/local/bin/v4l2rtspserver" ]
 CMD [ "-S" ]

Dockerfile.arm64

@@ -5,16 +5,14 @@ COPY . /v4l2rtspserver
 
 ARG ARCH=arm64
 
-ENV DEBIAN_FRONTEND=noninteractive
-
 RUN apt-get update \
-        && apt-get install -y --no-install-recommends ca-certificates xz-utils cmake make pkg-config git wget gcc-aarch64-linux-gnu g++-aarch64-linux-gnu \
+        && DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends ca-certificates xz-utils cmake make pkg-config git wget gcc-aarch64-linux-gnu g++-aarch64-linux-gnu \
         && cmake -DCMAKE_SYSTEM_PROCESSOR=${ARCH} -DCMAKE_SYSTEM_NAME=Linux -DCMAKE_C_COMPILER=aarch64-linux-gnu-gcc -DCMAKE_CXX_COMPILER=aarch64-linux-gnu-g++ -DCMAKE_FIND_ROOT_PATH_MODE_PROGRAM=NEVER -DCMAKE_FIND_ROOT_PATH_MODE_INCLUDE=ONLY -DCMAKE_FIND_ROOT_PATH_MODE_LIBRARY=ONLY -DCMAKE_FIND_ROOT_PATH_MODE_PACKAGE=ONLY . \
 	&& make install \
 	&& apt-get clean && rm -rf /var/lib/apt/lists/
 
 
-FROM arm64v8/ubuntu
+FROM arm64v8/ubuntu:20.04
 
 WORKDIR /usr/local/share/v4l2rtspserver
 COPY --from=builder /usr/local/bin/ /usr/local/bin/